DATE: 1856

MAKER: POWELL & LEALAND

SERIAL NUMBER: none but dated 1856

MODEL: 'Improved Large First Class Microscope'

DESCRIPTION: This microscope, unfortunately no longer in my collection, is signed and dated: Powell & Lealand, 4 Seymour Place, Euston Square, London , 1856. It has a minimum height of 35 cm with the eyepiece in place. It arises from a large tripod, the type of which was to become one of the hallmarks of these makers. The triangular bar limb has rack and pinion coarse focus. Fine focus is via long lever from the rear top of the arm. The arm could rotate to the side to allow easy access to the stage, and return to the center where a stop ensures centration. There are two strutts to steady the optical tube. The relatively thin (for the time) mechanical stage encorporates the concentric X and Y controls after Turrell. In addition, the slide-holding portion can independently rotate by hand. A rack and pinion substage is present. The mirror is attached on one side only to a quadrant of brass articulated to two arms, allowing very oblique illumination. A fine non-achromatic condenser was present. There were also six objectives, and a single eyepiece still with the microscope.

HISTORY OF THE POWELL & LEALAND FIRST CLASS MICROSCOPES.

This is one of the earliest known examples of this version of Powell & Lealand's microscopes. According to Hogg (4th edition, 1859) it was, at the time, Powell and Lealand's 'Number 1' stand and was referred to as the 'Improved Large First Class Microscope.' This model was larger than their earlier first-class version, (often incorrectly called a number 3), and while not referred to as the 'Number 2' was clearly the prototype for that later instrument. This microscope differs from the later number 2 in that the housing for the triangular bar is two-tiered, similar to the earlier smaller models. According to Hogg, accessories included a dark-well adapter, and a condenser with five central stops and nine apertures each with independent movements. As shown in the illustration to the left, an Amici prism on stand(similar to the Amici Lenticular oblique illuminator in this collection), was sometimes used to provide increased obliquity of illumination 'for test objects.'

According to Nelson's classic paper on P & L stands, a stand introduced in 1851 had many features similar to this one, but the substage was simply attached to the bottom of the stage. He also noted that Thomas Powell had one of those, similar to this one but without the separate substage, in his possession dated 1855. Since the example shown above has a separate substage assembly attached to the tailpiece, and is dated 1856, it is likely that 1855 or 1856 was the first year that the model shown on the top of this page was produced. That instrument, with rack and pinion substage, was first described, though not pictured, in the 1856 edition of 'The Microscope and its Revelations' by Carpenter in 1856.

Other examples of the model shown at the top of this page include one dated 1857, found in the booklet 'Microscopes from the Frank Collection' and another, originally belonging to Lionel S. Beale is in the collection of the R.M.S. Still another was sold in March of 1996 by Sotheby's.